"George White" bravely wrote to "Greg Mayman" (05 Feb
04  22:51:31)
 --- on the heady topic of "BAG OF CHIPS"

 GM> .  +5v rail------------+-----------
 GM> .                      |           |
 GM> .                 ------------    4700
 GM> .  +2.5v ref ----| -          |    |
 GM> .                |  1/4 LM339 |----+---- out
 GM> .    in ---------| +          |
 GM> .                 ------------
 GM> .                      |
 GM> .  -5v rail------------

 GW> It really needs some +ve feedback to make it into a schmitt trigger
 GW> circuit to avoid instability around the switching point on slow
 GW> signals. That needs 2 more resistors, some series input impedance (say
 GW> 10k) and one from "out" to 339 input (say 100k).

I thought comparators already had a little bit of feedback internally,
not sure though? Otherwise both why create a special purpose device
called a comparator ic and why wouldn't one simply use an opamp
instead?

 Mike
 ****

... # <--- electrocuted tribble
--- Blue Wave/DOS v2.30